研究报告
万仲豪,李孟,张倩.间苯二胺改性磁性壳聚糖对六价铬的还原-吸附协同作用机制研究[J].环境科学学报,2018,38(8):3118-3126
间苯二胺改性磁性壳聚糖对六价铬的还原-吸附协同作用机制研究
- Cr(VI) removal by using magnetic chitosan particles modified by mPD
- 基金项目：国家自然科学基金（No.20876122）
- 作者
- 单位
- 万仲豪
- 武汉理工大学土建学院, 武汉 430070
- 李孟
- 武汉理工大学土建学院, 武汉 430070
- 张倩
- 武汉理工大学土建学院, 武汉 430070
- 摘要：通过改进后的方法制备出具有良好颗粒形态的磁性壳聚糖颗粒，并使用间苯二胺（mPD）对其进行改性，在颗粒表面形成了一层含有大量含氮官能团的有机壳层，有效改善了颗粒的比表面积和活性官能团数量.通过序批实验法探究mPD改性磁性壳聚糖颗粒对六价铬Cr（VI）的吸附行为，实验结果显示初始pH为酸性有利于其对Cr（VI）的去除；吸附行为复合拟二级动力学模型，以化学吸附为主；在25℃、pH<3条件下，由Langmuir等温线计算得吸附量可以达到212.21 mg·g-1，优于此前报道过的很多非纳米级新型磁性吸附剂；通过Redlich-Peterson模型的拟合和吸附反应前后的X射线光电子能谱分析，可知mPD改性磁性壳聚糖颗粒对六价铬Cr（VI）的去除是通过氧化还原反应和吸附作用协同进行的；经过6次吸附-解吸再生过程，mPD改性磁性壳聚糖颗粒仍具有100 mg·g-1以上的吸附能力.综上，mPD改性磁性壳聚糖颗粒体现出其对Cr（VI）突出的去除性能，同时具有便于分离和再生能力强等特点，对于应用于含铬废水的处理具有良好的前景.
- Abstract：To obtain a high-efficiency adsorbent for the Cr(VI) removal, mPD was applied to modify magnetic chitosan particles which was yielded by ameliorated fabrication process. After modification, more nitrogenous functional groups were grafted on the surface of adsorbent forming a shell-layer configuration. After analysis of adsorption process, results indicated that acid environment was advantageous to the Cr(VI) removal. Pseudo second-order was more suitable to fit the data which denoted that chemical adsorption dominated. On conditions of 25℃ and pH<3, maximal Cr(VI) removal amount of 212.21 mg·g-1 was obtained by fitting of Langmuir. By analysis of Redlich-Peterson modeling and XPS before and after adsorption, concurrent redox reaction and adsorption in interaction between adsorbent and Cr(VI) were revealed. After six cycling times, removal capacity of modified adsorbent still attained 100 mg·g-1. In conclusion, modified magnetic chitosan particles which were distinctive for Cr(VI) removal beside of its separate capacity and regenerative feature were potential for treatment of Cr(VI)-containing wastewater.
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